A coupling structure for coupling a heat exchanger and an external pipe is, for example, described in U.S. Pat. No. 5,765,877. The disclosed coupling structure includes the external pipe having a male joint part, a connector having a female joint part with openings, and an engagement member having arced projections. The connector is arranged on a fixing part formed on a header tank of the heat exchanger such as a condenser. The arced projections of the engagement member have elasticity in a radial direction.
In a condition that the arced projections are fitted in the opening of the female joint part from an inner peripheral side, the male joint part of the pipe is inserted into the female joint part. At this time, the male joint part enters the female joint part while pressing the arced projections in a radially outward direction against the elasticity.
When the male joint part is brought into contact with a rear end of the female joint part after passing through the arced projections, the arced projections return to original positions by the elasticity. As a result, the male joint part is received between the female joint part and the engagement member, and hence the pipe is coupled to the connector. In other words, the pipe is coupled to the connector through the engagement member.
For example, a condenser for a vehicular air conditioner is mounted at a front portion in an engine compartment, and is connected to devices of a refrigerant cycle, such as a compressor and an expansion valve, through refrigerant pipes. To ease coupling of the condenser to the refrigerant pipes, connector are generally arranged to face front so that the coupling is performed in front of the condenser.
However, in the coupling structure disclosed in U.S. Pat. No. 5,765,877, the fixing part between the connector and the header tank, the female joint part and the male joint part are linearly disposed. Thus, an entire length of the coupling structure increases. That is, a projected length of the coupling structure in a frontward direction increases.